The invention relates to a tool for helically coiled wire inserts and, more particularly, to a mechanical tool for extracting and adjusting tangless helical coil inserts.
Tools for the removal of helically coiled wire inserts are well known. Generally, these tools have a tapered blade with a pair of knife edges that are driven into the inner diameter threads of the insert. When using these tools to extract an insert, however, the insert is often permanently damaged. Thus, these tools are not useful for adjusting the placement of the insert or removing the insert for reuse.
A removal tool for tangless helically coiled wire inserts is described in U.S. Pat. No. 4,553,303 and includes a mandrel having a threaded lead portion and a pivotable pawl inserted in a groove below the threaded portion so that the pawl can engage a recess in the trailing end of the insert in order to extract the insert from the tapped hole. This pivotable pawl automatically engages the insert when the mandrel is pulled back, allowing the mandrel to extract the tangless insert. However, this known extraction tool is a relatively complicated design, and suffers from increased risks of malfunction. Further, because each insert requires a tool of complimentary size, a set of tools taught by the aforementioned patent is relatively expensive.
An extraction and adjustment tool for tangless helically coiled wire inserts includes a mandrel with a threadless lead portion having a stationary driving tooth for engaging a recess in a trailing end of the insert for adjusting or extracting the insert from a tapped hole. The tool includes a handle portion having a bushing for selective reception of a mandrel adapted to fit a particular-size helically coiled wire insert. Once the tool is inserted into the internal diameter of the insert, the stationary driving tooth engages the recess in the trailing end of the insert for extracting or adjusting an incorrectly installed insert.